OF THOSE ghosts that are simply ghosts I have no fear. Some persons whistle when they pass country graveyards after dark in order, they say, to keep up courage; for the same reason I sometimes whistle on Broadway. Specters are harmless if they do not assume material form. The apparitions on the Chesapeake and Ohio canal towpath soon lost their ethereal quality in our vision and the unearthly noise that accompanied their manifestation translated itself into "you black-hearted, ornery, low-lifed beggar--geddap!" There was a familiar rattle of harness. The specters moved again, but more quickly this time. Against the black infiniteness of the mountains across the river were the shadowy forms of a pair of gray mules hitched in tandem. Wearily they plodded off, and moving slowly, tediously, silently behind them a canal boat followed along at the end of an invisible towline. A canal boat at night is a great hulk of hush. Its silence is positively uncanny. A few ripples momentarily disturb the placid surface of the water but as they swirl around the craft they seem to beckon a state of funereal quietude. You can hardly blame the midnight driver of the canal boat for his profane vociferousness in addressing his mules. His voice alone breaks the death-like stillness. After the lock has been passed and the patient animals take up their gait, even he is overcome by the environment and relapses into drowsy silence. At intervals through the night other specters appeared over there on the towpath and their advent invariably was heralded by the same hair-raising shouts. The noise of cussing the poor mules followed as certainly as the agonizing "low music" during tense moments in a melodrama. Tardy dawn ushered in a gloomy day. We placed our "canned heat" range on a lumber pile beside the North Branch lockhouse and had our coffee and bacon progressing satisfactorily toward the proper elements of an al fresco breakfast when rain began to fall. We retreated to the boat. The rain continued unabated and we breakfasted on board. Inasmuch as we were obliged to keep the curtains down and tuck the baggage under a poncho, it was impracticable--we thought--to proceed on our journey. The locktender's office at North Branch has seen service for more than half a century. We can testify to this because after we had sought its shelter and read all the magazines bought on the beginning of the trip we turned to a perusal of the lockmaster's records. These books date back to the 60's and it was fascinating to read on the faded pages the entries for the boats and cargoes of a by-gone era. The boats now operating are distinguished by numbers from 1 to 100, but in the old days they bore names, suggestive, no doubt, of their architecture and other characteristics, or of the ambition of their owners.